Invalid services config: service[selectuserbooks] return_type is mandatory

stack traceback:
/home/centos/work/tdg/common/config_checks.lua:10: in function 'assert'
/home/centos/work/tdg/input_processor/services/config.lua:39: in function 'validate_service'

return get_the_category_list(' ', '', $post_id);

/* Color in Mega Menu */
.jeg_newsfeed_subcat li.active {
background-color: red;
}

#include <iostream>
#include<stack>
using namespace std;

int main()

/* Custom Content Attribute */
function change_content_attr( $attr, $name, $term_id ) {
/* For Category */
if ( 'jnews_category_' === $name ) {
$attr['sort_by'] = 'popular_post';

SELECT
TOURNUMMER AS "Tour number",
VON_LAND AS "Sender country",
VON_ORT1 AS "Sender City",
VON_PLZ AS "Sender POST code",

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Pleasedontcode thanks you for automatic code generation! Enjoy your code!

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#include <fcntl.h>
#include <libfreenect.h>
#include <libfreenect_sync.h>
#include <string.h>
#include <unistd.h>

/* Add content after body */
function add_content_after_body() {
?>
<style>
.wrapper_facebook_promote {

text = input().upper()

unique_symbols = ""
current_symbol = ""
repetitions = ""